Finely divided fuel burner



March 7, 1944. w. F. OBERHUBER FINELY DIVIDED FUEL BURNER Filed July 1,1940 I5 Sheets-Sheet 1 \INVENTOR.

WM 5*. 0m

' WMV ATTORNEYS.

March 7, 1944. w, QBERHUBER 2,343,572

FINELY DIVIDED FUEL BURNER Filed July 1, 1940 3 Sheets-Sheet 2 INVENTOR.

9 ATTORNEY).

March 7, 1944. w QBERHUBER 2,343,572

FINELY DIVIDED FUEL BURNER Filed July 1. 1940 3 Sheets-Sheet 5 H 30b 40g III!IIII/IIIIIIIIIIIIIIIIIIIIII: I

NVENTOR' WM 5% h wwvw ATTORNEY-5'.

Patented Mar. 7, 1944 FINELY DIVIDED FUEL BURNER William F. Oberhuber,Lansdowne, Pa., assignor to Combustion Engineering Company, Inc., NewYork, N. Y., a corporation of Delaware Application July 1, 1940, SerialNo. 343,328

8 Claims.

This invention relates to fuel burners for use in pulverized coalburning furnaces and is particularly useful in furnaces in which thefuel is introduced by what is known as the tangential method of firing.

The primary object of my invention is the provision of burner meansadapted to be adjusted in a simple and effective manner to vary theangle of discharge of the fuel and air streams into the furnace.

A more specific object of my invention is the provision of adjustabletip means for burners of the above character whereby the angle ofdischarging fuel and air streams may be varied while still maintainingeffective admixture and,

- therefore, an even flame.

How the foregoing, together with such other objects and advantages asmay hereinafter appear or are incident to my invention, are realized isillustrated in preferred form in the accompanying drawings whereinFigure 1 is a sectional elevational view 'of a burner constructed inaccordance with my invention with the casing and the lower fuel nozzleand adjustable tip means shown in section as taken substantially on theline I-i of Figure 2;

Figure 2 is a plan section taken on the line 2-2 of Figure 1, but withthe fuel nozzle and certain associated parts appearing in full planview;

Figure 3 is an end view of one of the burner nozzles looking toward theleft in Figure 1;

Figure 4 is a diagrammatic plan view of a furnace showing the burners ofmy invention mounted for tangential firing;

Figure 5 is a longitudinal section through a modified form of burner,the section being taken on the line 5-5 of Figure 6 Figure 6 is a plansection taken on the line 8-6 of Figure 5;

Figure 7 is a fragmentary section taken on the line 5-1 of Figure 8,illustrating a modification of my invention; and

Figure 8 is a fragmentary vertical section taken on the line 8-8 ofFigure '7.

Referring to Figures 1, 2 and 3, the burner comprises, in general, anair casing A, in this instance divided into three superimposed airchambers ill, in each of which a fuel nozzle B and associated adjustabletip means C is located. A top air chamber II and a bottom air chamber l2may also be provided. In order to form the chambers ill the rear portionof the casing is provided with a plurality of horizontal partitions l3and the front portion with a pluralityof horizontal partitions H.Vertical side members l5 extend between the partitions It so as to formrectangular passages l6 which open at the rear into the air chambers l0and at the front into the furnace chamber D. Air inlets I! for theadmission of air, preferably preheated, to the chambers III areprovided, Suitable air dampers (not shown) are provided to control theadmission of the air.

The fuel nozzles B, to which pulverized coal is led as by means of pipesl8, are supported in the casing by means of supporting members l9, andare so positioned that their nozzle portions 26 are located in the.passages IE, it being noted that the nozzle portions merge from a roundcross-section 2| at the rear to a rectangular cross-section 22 at thefront, as clearly shown in Figure 3.

The adjustable tip means C for each nozzle comprises an innerrectangular shell 23 corresponding to the rectangular discharge end ofthe nozzle through which the fuel discharging from the fuel nozzlepasses, and an outer rectangular shell 24 of larger size which providesan air passage 25 in surrounding relation to the inner shell. The outershell 26 flares outwardly toward the back, and air from the air casingenters the enlarged end of the passage 25 and dis charges through thesmaller end into the furnace chamber. At the sides of the passages i6flaring plates 26 are preferably employed to direct the air into thepassage 25. A plurality of openings 2'! are provided in the plates 26 topermit some air to pass therethrough and thus prevent any tendency forthe creation of a vacuum in front of the plates.

In order to provide for adjustment of the tip means C it is pivotallymounted on the end por tion of the nozzle B by means of verticallydisposed pivot pins 28 which fit the holes 2% in the top and bottomwalls of the inner shell 23. A threaded adjusting rod 35 is'adjusta-blysecured adjacent one end to the casing A by means of a bracket 3i andadjusting and locking nuts 32 located exteriorly of the air casing. Thisrod is connected at its other end to a link 33 which, in turn, isconnected to an arm 34 rigidly secured to the inner shell 23.

Vertically extending curved members 35 are secured to the flattenedsides of the nozzle at its discharge end to cooperate with the curvedupright portions 36 of the inner shell 23 of the tip C so as to maintaina joint between the nozzle and the tip in any adjusted position of thetip, it being noted that the curve of these cooperating portions isstruck from the center of the pivot pins 28.

The outer shell 24 of the tip is secured in fixed spaced relation to theinner shell 23 by suitable braces 31, and it will thus be seen that therelation of the surrounding air passage 25 to the inner fuel passage isnot altered in any position of adjustment of the tip. Thus, the tip Cmay be moved into any desired angular position of adjustment withoutaltering the angle of the air stream issuing from the passage 25relative to the angle of the fuel stream issuing from the nozzle B. Thisis of importance in order to obtain proper firing conditions because, ifthese relative angles were changed, improper admixture of fuel and airwould result, certain portions of the flame being provided withinadequate air for complete combustion, and other portions having toomuch air. This would result in ineffective combustion and an unevenfiame. For example, if the angle of the fuel stream were altered withrespect to the air stream so as to be directed at an angle to the airstream, the resulting flame at the side where the larger amount of airis delivered would be bright, while on the other side where the smalleramount of air is delivered would be smoky. To avoid this condition Ihave provided an adjustable tip having fixed fuel and air passagesproviding proper admixture, which is bodily adjusted to vary the angleof discharge of the burner.

Referring now to Figure 4, I have therein diagrammatically illustratedan application of my invention to a pulverized coal burning furnacewhereby tangential firing is obtained. The burners B are located at thecorners of the furnace and positioned so as to deliver their streams ina direction tangent to an imaginary cylinder, indicated at E, having itsaxis extending vertically. As has been pointed out above, the angle ofthe streams discharging from the burners, indicated by the dot-and-dashlines F, may be altered by adjusting the angle of the tips C and thiswithout altering the quality of the flame.

In Figures and 6 I have illustrated adjustable tip means C of modifiedform provided with a central fuel passage 38, and side air passages 39,39. The outer walls 40 of the passages 39 are braced from the innerwalls M as by means of plates 42 so that the air and fuel streams aremaintained in fixed relation in all positions of adjustment of the tip.The tip C is pivotally mounted on the nozzle B by means of the pivotpins 280. and adjustment is afforded by means of the adjusting rod 30aconnected to the tip at 301) at one end and adjustably supportedadjacent its other end by means of a bracket Ella and lock nuts 32a. Inthis modification I have shown the nozzle B directed downwardly asviewed in Figure 5.

While I have shown the tip means in Figures 1, 2, 3, 5 and 6 as beingangularly adjustable on a substantially vertical axis only, I alsocontemplate having them universally adjustable, for example, asillustrated in Figures '7 and 8. In these figures the nozzle tip meanscomprises the tip members C and C". The member C is of rectangular formcorresponding to the rectangular discharge end of the nozzle B" and ispivotally mounted on the horizontally disposed pivot pins 43 carried bythe end portion of the nozzle, it being pointed out that curved surfaces44 are provided on the nozzle which cooperate with the curved surfaces45 on the member C.

The member C comprises an inner rectangular shell 46 corresponding tothe rectangular discharge end of the member C through which the fuelpasses, and an outer rectangular shell 41 of larger size which providesan air passage 48 in surrounding relation to the inner shell 48 and themember C.

The member C" is pivotaliy mounted on the vertically disposed pivotmeans 49 carried by the member C'. Vertically extending curved members50 are secured to the sides of the member C to cooperate with the curvedsurfaces 5| of the inner shell 46.

The nozzle tip means may be adjusted into various positions ofadjustment by suitable adjusting means such, for example, as the arms34a and 34b corresponding to the arm 34 of Figures 1 and 2, and operableby adjusting rods similar to the rod 30 of those figures. Adjustment ofthe arm 34a adjusts the tip means on the upright pivot pins 49, andadjustment of the arm 34?) adjusts the tip means on the horizontal pivotpins '23 so that by manipulating the two adjusting rods substantiallyuniversal angular adjustment may be obtained.

The advantage of adjustment of the tip means vertically is that thelevel of the flame may be altered to suit coals having ash of differentcharacteristics. For example, with a coal having low melting point ashit is desirable to keep the body of the flame as low as possible in thefurnace in order to minimize slagging difficulties in the boiler tubes.With coal having high melting point ash the flame may be carried higherin the furnace.

I claim:

1. A finely divided fuel burner for furnaces comprising an air casing,means mounted in a wall of the furnace providing an air discharge.outlet in said casing, a fuel nozzle mounted in said casing in fixedrelation thereto to discharge fuel through said air discharge outlet,tip means associated with said fuel nozzle and said air dischargeoutlet, said tip means having a central fuel passage and a surroundingsubstantially parallel air passage in fixed relation to each other andconstructed and arranged to separately discharge the air from saidpassage and the fuel from said passage directly into the furnace withthe air in substantially uniform surrounding relation to the dischargefrom the fuel passage, and means for bodily adjusting said tip means tovary the angle of discharge of the fuel and air.

2. A finely divided fuel burner for furnaces comprising an air casing,means mounted in a wall of the furnace providing an air discharge outletin said casing, a fuel nozzle mounted in said casing in fixed relationthereto to discharge fuel through said air discharge outlet, tip meansassociated with said fuel nozzle and said air discharge outlet, said tipmeans having a central fuel passage and a surrounding substantiallyparallel air passage in fixed relation to each other and constructed andarranged to separately discharge the air from said passage and the fuelfrom said passage directly into the furnace with the air insubstantially uniform surrounding relation to the discharge from thefuel passage, and means for bodily adjusting said tip means to vary theangle of discharge of the fuel and air, comprising a pivotal mountingfor the tip means, and an adjusting member connected to the tip meansand extending through said air casing.

3. A finely divided fuel burner for furnaces comprising an air casing,means mounted in a wall of the furnace providing an air discharge outletin said casing, a fuel nozzle mounted in said casing in fixed relationthereto to discharge fuel through said air discharge outlet, tip meansassociated with said fuel nozzle and said air dis.- charge outlet, saidtip means having a central fuel passage and a surrounding substantiallyparallel air passage in fixed relation to each other and constructed andarranged to separately dis-i charge the air from said passage and thefuel from said passage directly into the furnace with the air insubstantially uniform surrounding relation to the discharge from thefuel passage, and means for bodily adjusting said tip means to vary thele of discharge of the fuel and air, comp universal connection meansbetween the tip means and the nozzle, and adjusting m for said tipextending outside of the casing.

a. Afinely divided fuel burner for furnaces compg an air casing, meansmounted in a wall of the furnace providing an air discharge outlet insaid cas a fuel nozzle mounted in said casing in fixed relation theretoto discharge fuel through said air discharge outlet, tip meansassociated with said fuel nozzle and said air discharge outlet, thewalls of the tip being spaced from the walls of the air discharge outletto provide a passage therebetween, said tip means having a central fuelpassage and a surrounding substantially parallel air passage in fixedrelation to eachother and constructed and arranged to separatelydischarge the air from said passage and the fuel from said passagedirectly into the furnace with the airin substantially uniformsurrounding relation to the discharge from the fuel passage, means forbodily adjusting said tip means to vary the angle of discharge of thefuel and air, and means for directing the air into the air passages ofthe tip.

5. A finely divided fuel burner for furnaces comprising an air casing,means mounted in a wall of the furnace providing an air discharge outletin said casing, a fuel nozzle mounted in said casing in fixed relationthereto to discharge fuel through said air discharge-outlet, tip meansassociated with said fuel nozzle and said air discharge outlet, thewalls of the tip being spaced from the walls of theair discharge outletto provide a passage therebetween, said tip means having fuel and airpassages'in flxedrelation to each other through which fuel and air aredischarged, means for bodily adjusting said tip means to vary the angleof discharge of the fuel and air, and plate means directing the air intoair passages of the tip, said plate means having openings thereinleading to the e between the walls of the tip and the walls of thedischarge outlet.

6. A finely divided fuel burner for furnaces comprising an air casing,means mounted in a wall of the furnace providing an air discharge outletin said casing, a fuel nozzle mounted in said casing in fixed relationthereto t0 discharge fuel through said air discharge outlet, tip meansassociated with said fuel nozzle and'said air discharge outlet, thewalls of the tip being spaced from the walls of the air discharge outletto provide a passage therebetween, said tip means having fuel and airpassages in fixed relation to each other through which fuel and air aredischarged, plate. means directing the air into air passages of the tip,said plate means having openings therein leading to the passage betweenthe walls of the tip and the walls of the'discharge outlet, means forbodily adjusting said tip means to vary the angle of discharge of thefuel and air comprising universal connection means between the tip meansand the nozzle, adjuster means for said'tip means, and means for lockingsaid tip means in adjusted position.

7. A finely divided fuel burner for furnaces comprising an air casing,means mounted in a wall of the furnace providing an air discharge outletin said casing, a fuel nozzle mounted in said casing in fixed relationthereto to discharge fuel through said discharge outlet, tip meansassociated with said fuel nozzle and said air discharge outlet, thewalls of the tip being spaced from the walls of the air discharge outletto provide a passage therebetween, said tip means having fuel and airpassages in fixed relation to each other through which fuel and air aredischarged, plate means directing the air into the air passages of thetip, said plate means having openings therein leading to the passagebetween the walls of the tip and the walls of the discharge outlet,means for pivotally mounting said tip means for movement on asubstantially horizontal axis, means for pivotally mounting said tipmeans for movement on a substantially vertical axis, and means foradjusting said tip means to angular positions on said axes.

8. A finely divided fuel burner for fumaces' said fuel passage directlyinto the furnace with the air in substantially uniform surroundingrelation to the discharge from the fuel passage, means-for pivotallymounting said tip means for movement on a substantially horizontal axis,means for pivotally mounting said tip means for movement on asubstantially vertical axis, and means extending outside of the casingfor adlusting said tip means to angular positions on said axes.

